Today various kinds of portable electronic devices, e.g. notebook computers, cellular phones etc., rely on a touch pad (mouse pad) or a touch screen to sense the movement of a pointing device (often a finger) and to translate that movement into a cursor movement on a screen display of the electronic device. The two most popular pointing device sensing technologies are resistive and capacitive sensing technologies. On portable electronic devices these two technologies provide a convenient way to control a cursor as opposed to a USB cable connected computer mouse. The disadvantage for pointing device technology on portable electronic devices (e.g. iPhone, iPad, etc.) is a lack of cursor positioning accuracy by a pointing device, for example a finger or a stylus.
Although portability is an advantage for electronic devices comprising a notebook computer, the notebook computer is difficult to use in an office environment where cursor positioning accuracy is important. This problem is aggravated when the dimension of the notebook computer is reduced over years of development. This difficulty of usage leads to many users replacing the touch pad of the notebook computer with a computer mouse attached by a USB cable or more recently by a mouse connected by electronic signal means. In either case the coupled mouse requires extra hardware that must be ported along with the notebook computer.
US 2009/0160772 A1 (DePue et al.) is directed to an optical mouse with diffused optics, wherein an optical diffuser is configured to diffuse light from the light source that illuminates the tracking surface. U.S. Pat. No. 7,439,954 B2 (Theytaz et al.) is directed to a multi-light source computer pointing device wherein each light source has at least one unique illumination characteristic comprising impinging angle, light wavelength and light homogeneity. In U.S. Pat. No. 7,355,160 B2 (Cheah et al.) a pointing device and a method is directed to generating colored light in a plurality of wavelength bands, wherein a controller selects the wavelength band to illuminate the surface under the pointing device. U.S. Pat. No. 7,301,531 B2 (Wu) is directed to an optical mouse having a plurality of light sources of different color to eliminate the complementary color problem between the image light and the reflecting surface. U.S. Pat. No. 6,392,632 (Lee) is directed toward an optical cursor control device comprising an integrated camera, wherein captured images by an imaging device detects motion of the cursor control device. U.S. Patent Application No. 2005/0024336 (Xie et al.) is directed to the use of a Lambertian surface in a computer mouse to form a specular reflection, which provides an enhanced contrast to the image for purposes of navigation. U.S. Patent Application No. 2005/0024623 (Xie et al.) is directed to the use of a Lambertian surface and a narrow bandwidth of light in a computer mouse to form a narrow bandwidth specular reflection. U.S. Pat. No. 5,825,945 (Stolis et al.) is directed to a check imaging device using a Lambertian surface to project a highly uniform and diffused beam to an imaging site.